William and Kate's news gives us an opportunity to speak afresh of another royal baby, whose reign continues, and who claims the loyalty and allegiance of us all

The news that the Duke and Duchess of Cambridge are expecting a baby will surely bring joy to all except the most hard-hearted of republicans.

But as Christians there are extra reasons why we should not only be rejoicing but also praying –for William, for Kate (especially her health) and for the unborn baby also.

First of all, we should pray because we are commanded to. As Paul puts it in 1 Timothy 2v1-2: "I urge that supplications, prayers, intercessions, and thanksgivings should be made for everyone, for kings and all who are in high positions, so that we may lead a quiet and peaceable life in all godliness and dignity."

Over the centuries the Church of England's Prayer Book has been particularly helpful in enabling us to do this as a nation, with its thoughtful prayers for the monarch, including the request that whoever sits on the throne "may above all things seek thy honour and glory". If we believe that prayer makes a difference, that's a great thing to be praying!

Second, we should pray because, as figures above politics, members of the royal family have the capacity to set a tone for the nation untainted by the cut and thrust of Westminster. The Queen has been a selfless example of dignity, public service and quiet faithfulness in an era of tumultuous change. Let us pray that her successors, including this unborn child, may be able to demonstrate similar, stabilising qualities in years to come.

Third, for the foreseeable future at least, the monarch has an important role in the Church of England. As some have recently observed, the Queen is not "head" of the Anglican Church – it is Jesus Christ who has that role, as Colossians 1v18 makes clear – but she is the Supreme Governor. At the very least, we want to be praying that the person who occupies that position is sympathetic to Christian things, and even more preferably, that they have a living personal faith of their own. How wonderful it was to hear the Queen testify in her 2011 Christmas message that "God sent into the world a unique person – neither a philosopher nor a general, important though they are, but a Saviour, with the power to forgive".

And she then concluded: "It is my prayer that on this Christmas day we might all find room in our lives for the message of the angels and for the love of God through Christ our Lord." Wouldn't it be wonderful if those who come after her could speak in similar terms?

Fourthly, news of the royal baby reminds us of the preciousness of human life in general. A couple of months ago, Peter Saunders of the Christian Medical Fellowship wrote a blog pointing out the shocking fact that 27% of all human deaths in England and Wales in 2010 were due to abortion. He added: "Abortion is against the Hippocratic Oath, against the Declaration of Geneva, against the International Code of Medical Ethics and against the Judeo-Christian ethic on which the laws of our country were originally based." If the news of the royal pregnancy gives even one person pause to think of the value of a developing, unborn human life, and to act differently as a result, then that is a hugely positive spin-off. Let us pray that unborn children forming in the womb are no longer considered to be so cheaply disposable!

Finally, as Christmas approaches, William and Kate's news gives us an opportunity to speak afresh of another royal baby, whose reign continues, and who claims the loyalty and allegiance of us all... So let's get praying!